Does Mars have water 1

NASA "definitely" finds liquid water on Mars

All of these features can be explained by the notion that water runs down the marsh slopes and darkens their surface, says Alfred McEwen of the University of Arizona. However, there was one problem: "We had no direct evidence of the presence of water," he says. "It's just a guess."

The team has since linked the streaks to hydrous salts found in four different areas where the streaks also appear. These salts are so-called perchlorates, which can bind water molecules in their crystal structures.

"The presence of hydrous salts in these rivulets means that the streaks are caused by water that is currently on Mars," says Ojha.

DOES MARS SWEAT?

Of course, the big question about the origin of this water immediately arises: Where does it come from? A possible origin could be water-bearing layers or melting ice beneath the surface. This would mean that Mars practically "sweats". As the planet warms up, salt water seeps through its pores and trickles down the slopes.

The water could also come from the atmosphere, which is most likely to the team. In this scenario, the salts absorb water vapor from the Martian atmosphere.

"When the humidity in the Martian atmosphere gets high enough, the perchlorates absorb the atmospheric water until the salt dissolves and forms a liquid solution," says Mary Beth Wilhelm of NASA's Ames Research Center.

Wherever the water comes from, it is no surprise that there is water on Mars. Whole landscapes on Mars were formed by water (including an ancient ocean miles deep), albeit billions of years ago, when the planet was warmer and richer in water. The many spacecraft that are currently being used to survey the surface of Mars are sending increasing amounts of data suggesting that water used to be ubiquitous.

So far, however, there has been little evidence that water flows on today's surface. What this means for the bigger picture of planetary research and the search for life on planets other than Earth is still a mystery.

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Article published in English on September 28, 2015